55 



sulphuric acid and determine the nitrogen by the Gunning method. To a second 100 

 cc of the filtrate add f> ce of phosphotungstic acid, 20 per cent solution; shake thor- 

 oughly, allow to settle, and filter by decantation. Wash slightly with water. Con- 

 centrate the filtrate with 5 cc of sulphuric acid in Kjeldahl flask and determine the 

 nitrogen as amid. 



1 ).Miurt the amid nitrogen from the nitrogen found in the first fraction to obtain the 

 nitrogen as globulin and albumen. This figure times 6. 25 gives globulin anrl albumen. 



ALCOHOL SOLUBLE PROTEINS (GLIADIN). 



\Veigh 4 grams of flour into a 500 cc Erlenmeyer flask, add 200 cc of alcohol 0.90 sp. gr. 



Shak ra.-ionally during three hours. Let stand 12 hours. Filter through a dried 



filter. Kvaporate th> alcohol from 100 cc of the filtrate. after the addition of 5 cc of 

 sulphuri'- arid and determine the nitrogen as alcohol soluble nitrogen. This figure, 

 !.-.- tin* amid nitrogen, gives the alcohol soluble proteid nitrogen or gliadin. 



'.11 TIMS DETERMINATION BY DIFFERENCE). 



heduct from the total nitrogen the salt soluble nitrogen plus the gliadin. This 

 time- i ;_'."> gives theglutenin. 



i.l.IAUIN H\ roLAKIZATION (METHOD OF SNYDER). 



Weigh r>.!7 irrams of flour into a 300 cc flask. Add 100 cc of 0.90 sp. gr. alcohol. 

 Shak'- at interval- during three hours and let stand overnight. Filter through a dry 

 folded filter. I'olan/e in a 220 mm tube. Precipitate the proteids in 50 cc of the 

 filtrate with ."> cc of Millon's reagent. Shake, tilter,and polarize the filtrate in a 220 mm 

 ml). Aill "><> per , . 'lit to i he reading and deduct the sum from the first reading. This 

 dii't'eivner times. 0.2 gives the percent of nitrogen as gliadin. 



FAT DETERMINATION (BASSETT). 



An H'fort was made to discover a method whereby the time for determining fat 

 and mi i-t iin- in cereal samples, especially flour, could be much shortened and without 

 a sacrifice of accura<\ IIP. Bassett, of the North Dakota laboratory, was assigned 

 some work along thi< line, the results of which are embodied in the following: 



Fat in flour has be-n determined usually by the method given by Leach, which is 



outlined so as to be applicable to all food and feeding stuffs. However, in making fat 



on tlour l'\ l.e.i. h'- method considerable time is required, and unless 



are taken the analyst could never check himself. This, in any 



method, in. li< -at.- inaccuracy. In examining the difficulties which might arise to 



i hi.- ni. -i hod, it was especially noted that oxidation might take place in drying 



th- tlour in a hot -water o\en, as is generally practiced, since the fat in the flour is in a 



tine state- of di\ i-ion, \\ liich gives the most favorable conditions for oxidation. Again, 



tin- .-pi--ial j>r. < aution <,f removing the last trace of moisture from the flour seemed 



-sary point \vh.-n the ether, as generally employed, contained probably 



ten times more water than was found in the dried flour. 



The extra- t ion l>y the I.eaeh extractor is also slow, requiring sixteen hours, and in 

 apparatus arranged in su h a manner that it cannot always be run with safety over- 

 night. This mean*, then, three full workingdays before a determination can be made 

 on,- for the inoi-ture determination and two for the fat determination. 



In order to avoid these difficulties, the following method was developed: 



Ten grams of flour were weighed into a tared gooch crucible, then placed in the 

 ordinary u'ooeh funnel, which was inserted into a rubber stopper in the top of a low 

 bell jar! whieh rested upon a ground -glass plate. Under the bell-jar and directly under 

 the gooch funnel was placed a second glass plate to avoid the possibility of getting 

 vaseline on the bulb, which was to catch the filtrate, vaseline being used to make an 

 air-tight joint between the bell-jar and ground-glass plate. The gooch was now filled 

 with ether six times, each time drawing off with the filter pump. The ether extract 

 was collected in a bulb similar to those with a Soxhlet apparatus. This bulb was then 

 removed and connected with a Liebig's condenser, and the ether distilled off with a 

 mdle-power incandescent bulb, this being used as it avoided the possibility of the 

 vapors of ether catching fire, and also has the additional advantage of not being so hot 



